The present invention is generally related to methods for machining material and more particularly to a method and apparatus for machining nontraditional materials such as diamond, ceramics, and the like.
Known to the art are various apparatus and methods for machining materials. Such apparatus include those commonly utilized in manufacturing traditional materials (i.e., metals and the like). However, such manufacturing apparatus are poorly suited for machining nontraditional materials (i.e., diamond, ceramics and the like).
Advancements in the material sciences has produced a myriad of new materials. Many of these materials are hard and brittle and therefore difficult or impossible to successfully to drill or shape with standard machinery equipment. Lasers have been utilized with some limited success in cutting and drilling some of these new materials. However, the continuous or long pulsed lasers (nanosecond or longer) couple ineffectively with the surface of the material and a great portion of the laser energy goes into heating the plasma which produce large thermal gradients in the processed material which adversely affect the materials properties near the laser interaction region. Additionally, the long pulsed lasers known to the machining art are limited to several hundred pulses per second. These fundamental limitations, in the machining art, limit the potential use for a wide array of important new materials.
Femtosecond pulse generating lasers are known to the art. Lasers of this type are capable of generating pulse lengths presently as short as 5 femtoseconds (5xc3x9710xe2x88x9215 seconds) with pulse frequencies presently as high as 10 KHz. Various methods for utilizing such lasers are also known and described in the art. For example, a method of producing electrical pulses having an extremely narrow pulse width is described by Rauscher, et al. (U.S. Pat. No. 4,870,295); a method of detecting atomic and molecular motion is described by McClelland, et al. (U.S. Pat. No. 5,151,594); a femtosecond ultraviolet laser utilizing ultra-thin beta barium is described by Edelstein, et al. (U.S. Pat. No. 5,034,951); a broadly tunable high repetition rate femtosecond optical parametric oscillator is described by Edelstein, et al. (U.S. Pat. No. 5,017,806); a real time method of processing picosecond and femtosecond laser pulses is described by Cutolo, et al. (U.S. Pat. No. 5,007,717); a method of obtaining ultra fast spectral data utilizing a femtosecond laser is described by Heilweil, et al. (U.S. Pat. No. 4,980,566); and a method of investigating surfaces at nanometer and picosecond resolution is described by Beha, et al. (U.S. Pat. No. 4,918,309). Additionally, Elsayed-Ali, et al. describes a femtosecond time-resolved thermomodulation of thin gold films having different crystal structures (Physical Review 47:13 599-13 610); and Reitze, et al. has measured the optical properties of liquid carbon utilizing a femtosecond spectrometer (Physical Review 45:2677-2693).
The present invention teaches various femtosecond machining and drilling apparatus and processes for fabricating tools and bulk materials and the like from both traditional and non-traditional materials. Also described are novel tools such as scalpels, and nozzles fabricated from the apparatus and processes according to the present invention. Likewise, the present invention may be utilized in a novel propulsion system, the production of new and unique materials formed from nanometer sized particles, and in surgical and dental procedures, for example, in the preparation of a tooth for a filling, and the like.